Capsule for treating ulcerative colitis

ABSTRACT

An object of the present invention is to obtain a capsule for treating ulcerative colitis which, when a capsule containing indigo is orally administered, acts more effectively than conventional ones and has less side effects of hepatotoxicity by not easily disintegrating in the stomach and small intestine but only in the large intestine. The present invention relates to a capsule for treating ulcerative colitis which disintegrates locally in the large intestine, comprising a drug-containing content, a protective layer coating the content and a film formed outside the protective layer, which are arranged concentrically, wherein the content is a content in which indigo, which is a drug for treating ulcerative colitis, is dispersed or dissolved, and the film is locally disintegrated in the large intestine.

TECHNICAL FIELD

The present invention is related to a capsule for treating ulcerativecolitis, specifically, a capsule for treating ulcerative colitis thatdoes not easily disintegrate in the stomach and small intestine whenorally administered, and disintegrates in the large intestine so thatindigo is delivered directly to the large intestine and the capsules area specific therapeutic formulation for ulcerative colitis.

BACKGROUND ART

Qing-Dai (

) is a crude component extracted from plants containing indigo, and hasbeen mainly used as an indigo dye. Chinese herbal medicines containingQing-Dai have been used for ulcerative colitis for a long time in China,but they have not been sufficiently scientifically verified.

In Gastroenterology: “Efficacy of Indigo naturalis in a MulticenterRandomized Controlled Trial of Patients with Ulcerative Colitis”, MakotoNaganuma et al., published online on Nov. 22, 2017 (Non PatentLiterature 1), in order to scientifically prove effectiveness ofQing-Dai against ulcerative colitis, a double-blind dose-responsecomparative trial, that compared oral administration of Qing-Dai inthree groups with daily doses of 0.5 g, 1.0 g and 2.0 g and placebo in86 patients with ulcerative colitis, was conducted. Its result indicatesthat the oral administration of Qing-Dai showed significant improvementin all doses and evaluation indexes when comparing to the placebo group.In this trial, it was shown that Qing-Dai would be expected to haveexcellent therapeutic effects on ulcerative colitis, which wasintractable and whose patient's quality of life (QOL) was extremelypoor.

However, the Ministry of Health, Labor and Welfare notified that “inpatients with ulcerative colitis who used Qing-Dai, it was found thatthere were a plurality of patients that exhibit pulmonary arterialhypertension,” (PSEHB/CND Notification No. 1227-9, Dec. 27, 2016 (NonPatent Literature 2)).

Pulmonary arterial hypertension is one of serious adverse effects.Therefore, instead of administration of Qing-Dai itself, a formulationto be delivered to the large intestine while suppressing the dose by apure medicinal active ingredient without impurities is required.

JP 2987576 B1 (Patent Literature 1) discloses a medicinal compositionwhich comprises an extract of Indigofera arrecta for treating gastriculcer and duodenal ulcer which are peptic ulcers. In examples of PatentLiterature 1, the extract of Indigofera arrecta is enclosed in a capsuleand administered to mice, and it is shown to be effective for pepticulcer. However, what is used in this literature is an extract ofIndigofera arrecta, not indigo itself, and the capsule used in thistechnique is a normal capsule used for oral administration to humans.

On the other hand, indigo, which is the main medicinal active ingredientof Qing-Dai, is an indole compound, and the indole compound has recentlyattracted attention as a substance that promotes mucosal healing. JP5383977 B1 (Patent Literature 2) discloses a pharmaceutical compositionfor treating and/or preventing Crohn's disease or ulcerative colitiscontaining indigo compounds such as indigo and isoindigo (particularly,meisoindigo). It is also described that the pharmaceutical compositionstake the form of capsules (see claim 1 and paragraphs [0045] to [0048]of Patent Literature 2). It is, however, merely mentioned as a capsulein Patent Literature 2 and its form is not explained at all.Administration in a capsule is not described in the examples of PatentLiterature 2. Those used in the examples of Patent Literature 2 arepellets of meisoindigo.

Patent Literature 3 describes a large intestine disintegrating capsule.However, the content of the capsule described in Patent Literature 3 ismainly lactic acid bacteria and water-soluble proteinaceous molecules,and are described to be used for the purpose of preventing deteriorationof quality due to pH and degrading enzymes. On the other hand, thecapsule for treating ulcerative colitis of the present invention has aproblem that the drug acts only on the large intestine to be treated.However, in this present invention, the content is indigo, which is amolecule having extremely poor solubility in water and oil. It cannot beexpected only from the description in Patent Literature 3 that indigo isactually administered to a living body and held without disintegratingin the stomach and small intestine, and disintegrates only in the largeintestine to act, and effects can be seen only in the large intestine.Therefore, the present invention cannot be easily completed by a personskilled in the art from the description in Patent Literature 3.

J. Gastroenterol. Vol. 51, 853-861 (2016) (Non Patent Literature 3)describes that indole compounds including indigo are therapeutic drugcandidates for ulcerative colitis, and the effect thereof is mediated byan aryl hydrocarbon receptor (AhR) which is one of mechanisms involvedin mucosal healing. Furthermore, J. Gastroenterology Vol. 52, 904-919(2017) (Non Patent Literature 4) describes that a mouse model of colitishad a therapeutic effect by administering Indigo naturaris (IN) powderor indigo powder, and that the action of IN and indigo occurs viabinding to an aryl hydrocarbon receptor (AhR) in a local mucous membrane(p. 914, right column, lines 30 to 32 of Non Patent Literature 4). Onthe other hand, the aryl hydrocarbon receptor (AhR) is also present inthe small intestine, and from the description of these literatures, itis expected that when an indole compound such as IN, indigo or isoindigocomes into contact with the small intestine, it is absorbed through thearyl hydrocarbon receptor (AhR) in the small intestine, and the sideeffects as described in Non Patent Literature 2 may occur.

Therefore, when a formulation containing an indole compound such asindigo is developed, contact with the small intestine as described inthe above literatures may increase absorption in the small intestine,which may trigger an onset of pulmonary arterial hypertension. Thus, aformulation to be delivered only to the large intestine is desired, inwhich, when a formulation containing indigo is orally administered, itdoes not disintegrate in the stomach and small intestine so that theindigo compound does not come into contact with the small intestine, anddisintegrates and exerts its effect only after being delivered to thelarge intestine.

CITATIONS LIST Patent Literature

Patent Literature 1: JP 2987576 B1

Patent Literature 2: JP 5383977 B1

Patent Literature 3: JP 5102401 B1

Non-Patent Literature

Non Patent Literature 1: Gastroenterology: Inpress “Efficacy of Indigonaturalis in a Multicenter Randomized Controlled Trial of Patients withUlcerative Colitis”, Makoto Naganuma et al., published online on Nov.22, 2017.

Non Patent Literature 2: PSEHB/CND Notification No. 1227-9, Dec. 27,2016

Non Patent Literature 3: J. Gastroenterol. Vol. 51, 853-861 (2016)

Non Patent Literature 4: J. Gastroenterology Vol. 52, 904-919 (2017)

SUMMARY OF INVENTION Technical Problems

An object of the present invention is to obtain a capsule for achievingless side effects and more effective action on ulcerative colitis thanconventional ones, in capsule technique, when the capsule includingindigo is orally administered to a patient having a disease of enteritisor the like.

Solutions to Problems

As a result of repeated intensive research to solve the above objects,the present inventors have found that when indigo is orally administeredto model animals induced colitis by sodium dextran sulfate in the formof a capsule (capsule that does not easily disintegrate in the stomachand small intestine and disintegrates in the large intestine), itfunctions more effectively on ulcerative colitis without causinghepatotoxicity (one of the side effects due to contact/absorption in thesmall intestine), and they have achieved the present invention. That is,the present invention provides a capsule for treating ulcerative colitiswhich disintegrates locally in the large intestine, which comprises adrug-containing content, a protective layer coating the content and afilm formed outside the protective layer exist, which are arrangedconcentrically, wherein the content is a content in which indigo, whichis an active ingredient for treating ulcerative colitis, is dispersed ordissolved, the protective layer contains an oily substance, the film isa film which chitosan powder is dispersed in a film base material of anatural water-soluble polymer, and the natural water-soluble polymer isa mixture of a first natural water-soluble polymer and a second naturalwater-soluble polymer, the first natural water-soluble polymer iscomposed of one or a mixture of at least two selected from the groupconsisting of gelatin, carrageenan, starch, agar, pullulan, modifiedstarch, alginic acid and mannan, and the second natural water-solublepolymer is composed of one or a mixture of at least two selected fromthe group consisting of pectin, gellan gum and curdlan.

The film preferably further contains a plasticizer.

It is preferred that the chitosan powder is of animal or plant origin,and amount of the chitosan powder falls within the range of 1 to 27% bymass, and amount of the second natural water-soluble polymer fallswithin the range of 1 to 24% by mass, based on the total weight of thedried film.

The film base material of the natural water-soluble polymer ispreferably a mixture of gelatin and pectin.

One selected from the group consisting of the content, the protectivelayer and the film or a combination selected from the group consistingof the content, the protective layer and the film, of the capsule fortreating ulcerative colitis, more preferably contains an adherablesubstance to an epithelial of large intestine, a substance increasingresidence time in the large intestine or a combination thereof.

An adherable substance to an epithelial of large intestine, a substanceincreasing residence time in the large intestine or a combinationthereof may be allowed to be present on the outer surface of the film ofthe capsule for treating ulcerative colitis.

The capsule for treating ulcerative colitis may comprise the contentwhich contains indigo powder and an adherable substance to an epithelialof large intestine, and the indigo powder may be blended or coated withan adherable substance to an epithelial of large intestine.

The capsule for treating ulcerative colitis is preferably for oraladministration.

It is preferred that the capsule for treating ulcerative colitis isadministered in amount of indigo per adult (60 kg) of 0.05 to 120mg/day, and preferably 0.05 to 20 mg/day.

In another embodiment of the present invention,

(1) a capsule for treating ulcerative colitis, which disintegrateslocally in the large intestine, including a drug-containing content, aprotective layer coating the content and a film formed outside theprotective layer, which are arranged concentrically, wherein the contentis a content in which indigo which is a drug for treating ulcerativecolitis, is dispersed or dissolved, the protective layer contains anoily substance, the film is a film which chitosan powder is dispersed ina film base material of a natural water-soluble polymer, and the naturalwater-soluble polymer is a mixture of a first natural water-solublepolymer and a second natural water-soluble polymer, the first naturalwater-soluble polymer is composed of one or a mixture of at least twoselected from the group consisting of gelatin, carrageenan, starch,agar, pullulan, modified starch, alginic acid and mannan, and the secondnatural water-soluble polymer is composed of one or a mixture of atleast two selected from the group consisting of pectin, gellan gum andcurdlan,

(2) the capsule for treating ulcerative colitis according to (1) above,in which the film further contains a plasticizer,

(3) the capsule for treating ulcerative colitis according to (1) or (2)above, in which the chitosan powder is of animal origin or plant origin,and amount of the chitosan powder falls within the range of 1 to 27% bymass, and amount of the second natural water-soluble polymer fallswithin the range of 1 to 24% by mass, based on the total weight of thedried film,

(4) the capsule for treating ulcerative colitis according to any one of(1) to (3) above, in which the film base material of the naturalwater-soluble polymer is a mixture of gelatin and pectin,

(5) the capsule for treating ulcerative colitis according to (1) to (4)above, which has been treated with an acidic solution in advance,

(6) the capsule for treating ulcerative colitis according to any one of(1) to (5) above, in which one selected from the group consisting of thecontent, the protective layer and the film or a combination thereoffurther contains an adherable substance to an epithelial of largeintestine, a substance increasing residence time in the large intestineor a combination thereof,

(7) the capsule for treating ulcerative colitis according to any one of(1) to (5) above, in which an adherable substance to an epithelial oflarge intestine, a substance increasing residence time in the largeintestine or a combination thereof is allowed to be present on the outersurface of the film,

(8) the capsule for treating ulcerative colitis according to any one of(1) to (5) above, including the content which contains indigo powder andan adherable substance to an epithelial of large intestine, wherein theindigo powder is blended or coated with the adherable substance to theepithelial of large intestine,

(9) the capsule for treating ulcerative colitis according to any one of(1) to (8) above, which is for oral administration,

(10) the capsule for treating ulcerative colitis according to any one of(1) to (9) above, which is administrated in amount of indigo per adult(60 kg) of 0.05 to 120 mg/day, and

(11) the capsule for treating ulcerative colitis according to (1) to (9)above, which is administrated in amount of indigo per adult (60 kg) of0.05 to 20 mg/day.

Advantageous Effects of Invention

According to the present invention, indigo which is a drug for treatingulcerative colitis is coated with a large intestine disintegratingcapsule, so that it suppresses disintegration in the stomach and smallintestine, and without being contacted to or absorbed in the stomach orsmall intestine, reaches the large intestine and disintegrates, and thedrug acts. Therefore, since indigo reaches the large intestine at a highconcentration without being dispersed in the upper gastrointestinaltract such as the stomach and small intestine, its effect is locallyexerted in the large intestine, and further, there is few concern ofside effects due to contact and absorption in the stomach and smallintestine. The effectiveness of the capsule for treating ulcerativecolitis of the present invention has been confirmed in mouseexperiments.

Qing-Dai has been known to be effective against ulcerative colitis as aChinese herbal medicine for a long time, and its main active ingredient,indigo, is not dispersed in upper gastrointestinal tracts (stomach andsmall intestine) and directly reaches the large intestine, whereby anexcellent effect of Qing-Dai has been confirmed. Although severepulmonary arterial hypertension and the like have been reported as sideeffects of indigo, these can be also expected to be alleviated.

In addition, when an adherable substance to an epithelial of largeintestine, a substance increasing residence time in the large intestineor a combination thereof is contained, in any part(s) of the capsule ofthe present invention, for example, the inside of the content, theprotective layer, the film or a combination thereof, or in the form of acoating on the outside of the film, the contact time of indigo in thelarge intestine is increased, and a greater therapeutic effect onulcerative colitis is expected.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a pictorial representation of the types of mice used in theexamples for easy understanding. The leftmost picture is a mouseadministered with 200 μL of sterilized water as a control, the secondfrom the left is a mouse administered with 5 indigo-containing capsulesA per day (the amount of indigo is 0.5 mg/day), and the rightmost is amouse administered with 15 indigo-containing capsules per day (theamount of indigo is 1.5 mg/day).

FIG. 2 is a graph representing changes in body weight (BW) of mice for 7days.

FIG. 3 is a graph representing results of disease activity index score(DAI score).

FIG. 4 is a graph representing results of measuring colon length.

FIG. 5 is a graph representing indigo hepatotoxicity confirmed withserum ALT index.

DESCRIPTION OF EMBODIMENTS

The capsule for treating ulcerative colitis which disintegrates locallyin the large intestine of the present invention is a capsule in which acontent containing indigo being an active ingredient for treatingulcerative colitis, a protective layer coating the content and a filmformed outside the protective layer, which are arranged concentrically.The content of the capsule will be described first.

The content of the capsule for treating ulcerative colitis of thepresent invention is a content in which indigo which is a drug fortreating ulcerative colitis is dispersed or dissolved. Indigo is acompound having the following chemical formula:

and is also used as a dye showing indigo color. Indigo is a pigmentcomponent of indigo and has been extracted from plants (Strobilanthescusia, Persicaria tinctoria) and the like, but is currently synthesizedfrom aniline. Qing-Dai is a crude component containing indigo, andalthough it may be used as the content of the present invention, asynthetic product (indigo) is preferably used, because it has a purityof 95% or more and controls side effects.

The content of the capsule for treating ulcerative colitis of thepresent invention contains indigo which is a drug for treatingulcerative colitis as described above, and indigo is suspended in anoily substance. The reason for suspending in an oily substance in thisway is that the content is not affected by a large amount of water andthe like that are present during capsule production. The oily substanceis non-fluid at room temperature, and examples thereof include ediblehardened oil and fat, sucrose fatty acid ester (SAIB), glycerin fattyacid ester and the like, and mixtures thereof. A particularly preferableoily substance is glycerin fatty acid ester, and examples thereofinclude glycerin fatty acid ester with a melting point of 32° C. or 42°C.

In the capsule for treating ulcerative colitis of the present invention,the amount of the drug (that is, indigo) in the above content usuallyfalls within the range of 0.1 to 40% by mass, preferably 0.5 to 30% bymass, and more preferably 1 to 20% by mass. When it is more than 40% bymass, encapsulation becomes difficult, and when it is less than 0.1% bymass, it becomes difficult to secure a desired dose. The amount ofindigo per capsule preferably falls within the range of 0.1 mg/cap to 20mg/cap, more preferably 0.1 mg/cap to 10 mg/cap, and further preferably0.1 mg/cap to 5 mg/cap. The content of the capsule for treatingulcerative colitis of the present invention may appropriately containpharmaceutically acceptable excipients, stabilizers, surfactants,adjuvants, foaming agents, or the like. The amount of the additiveagents is not particularly limited, but should not be amount thatinhibits an action of the capsule for treating ulcerative colitis of thepresent invention.

In the capsule for treating ulcerative colitis of the present invention,the content is generally covered with two layers (the protective layerand the film). The method of encapsulation is not particularly limited,but the most preferable method includes a method of dropping into acoagulating liquid using a triple nozzle generally called a droppingmethod (for example, JP 49-59789 A, JP 51-8176 A and JP 60-172343 A).

In the three-layer structure capsule of the present invention, aprotective layer is formed on a surface of the content. The protectivelayer contains an oily substance. The oily substance is the same as thatis formulated in the above content, but it is preferable to use an oilysubstance having a melting point 2 to 9° C. higher and preferably 2 to8° C. higher than the melting point of the content, so that hardening(or curing) can be controlled during cooling in the capsule formingprocess. When the difference in melting point is less than 2° C., thecontent and the protective layer would be mixed during cooling, and onthe contrary, when the difference in melting point is higher than 9° C.,the protective layer does not solidify, thereby hindering capsuleformation. Lecithin and silicon dioxide can be blended in the protectivelayer in order to adjust interfacial tension, viscosity or specificgravity.

The protective layer is further coated with a film. The film is a filmwhich chitosan powder is dispersed in a film base material of a naturalwater-soluble polymer, and the natural water-soluble polymer is amixture of a first natural water-soluble polymer and a second naturalwater-soluble polymer, the first natural water-soluble polymer iscomposed of one or a mixture of at least two selected from the groupconsisting of gelatin, carrageenan, starch, agar, pullulan, modifiedstarch, alginic acid and mannan, and the second natural water-solublepolymer is composed of one or a mixture of at least two selected fromthe group consisting of pectin, gellan gum and curdlan.

The natural water-soluble polymer used in the film base material of thecapsule of the present invention is preferably a combination of a firstnatural water-soluble polymer that imparts excellent mechanical strengthand film-forming ability and adhesiveness to a capsule to be obtained,and a second natural water-soluble polymer that imparts acid resistance,especially, gastric acid resistance. The first natural water-solublepolymer is composed of one or at least two selected from the groupconsisting of gelatin, carrageenan, starch, agar, pullulan, modifiedstarch, alginic acid and mannan, and the second natural water-solublepolymer is composed of one or at least two selected from the groupconsisting of pectin, gellan gum and curdlan.

Amount of the first natural water-soluble polymer falls within the rangeof 1 to 98% by mass, preferably 2 to 85% by mass, and more preferably 3to 70% by mass, based on the total weight of the dried film. When theamount of the first natural water-soluble polymer is less than 1% bymass, strength of the formed capsule is low, and when it exceeds 98% bymass, functions of acid resistance and large intestine disintegrationcannot be imparted.

Amount of the second natural water-soluble polymer falls within therange of 1 to 24% by mass, preferably 2 to 18% by mass, and morepreferably 3 to 6% by mass, based on the total weight of the dried film.When the amount of the second natural water-soluble polymer is less than1% by mass, the film of the formed capsule does not have sufficient acidresistance, and when it exceeds 24% by mass, the viscosity of the filmsolution becomes high, making it difficult to form a capsule.

The film of the capsule for treating ulcerative colitis of the presentinvention includes a film in which chitosan powder is dispersed in afilm base material of a natural water-soluble polymer. Chitosan isobtained by deacetylating chitin, which is a polysaccharide in whichN-acetyl-D-glucosamine units are linearly linked by β-1,4-bonds, byboiling treatment in concentrated alkali or the like, and the chitin iscontained in a crust of a crab or a shrimp, an insect epidermis,skeleton of a squid or the like, and cell walls of fungi such asmushrooms. It is desirable that the chitosan powder used in the capsuleof the present invention is of animal origin or plant origin, asdescribed above.

The particle size of the chitosan powder used in the capsule of thepresent invention falls within the range of 90% or more passing througha sieve with an opening size of 22 μm (580 mesh) to 90% or more passingthrough a sieve with an opening size of 355 μm (42 mesh), preferably 90%or more passing through a sieve with an opening size of 45 μm (330 mesh)to 90% or more passing through a sieve with an opening size of 250 μm(60 mesh), and more preferably 90% or more passing through a sieve withan opening size of 75 μm (200 mesh) to 90% or more pass through a sievewith an opening size of 180 μm (83 mesh), according to sieve teststandard JIS Z8801. When the particle size of the chitosan powder issmaller than 90% or more passing through a sieve with an opening size of22 μm (580 mesh), the viscosity of the natural water-soluble polymersolution in which the chitosan powder is dispersed becomes high, makingit difficult to form a capsule, and when it is larger than 90% or morepassing through a sieve with an opening size of 355 μm (42 mesh), thechitosan powder is difficult to be uniformly dispersed in the film,making it difficult to form a capsule and not exhibiting a stable largeintestine disintegrating function.

Amount of the chitosan powder falls within the range of 1 to 27% bymass, preferably 3 to 18% by mass, and more preferably 6 to 12% by mass,based on the total weight of the dried film. When the amount of thechitosan powder is less than 1% by mass, the large intestinedisintegrating function cannot be exhibited due to the small amount ofdispersed chitosan powder, and when it exceeds 27% by mass, the amountof dispersed chitosan powder is too large to form a capsule.

The film of the capsule for treating ulcerative colitis of the presentinvention may further contain a plasticizer in order to impartflexibility in a dry state, and examples of the plasticizer includeglycerin, sorbitol, and the like. Amount of the plasticizer falls withinthe range of 1 to 50% by mass, preferably 5 to 40% by mass, and morepreferably 15 to 30% by mass, based on the total weight of the driedfilm. When the amount of the plasticizer is less than 1% by mass, thefilm cannot withstand vacuum drying or may not maintain sufficientflexibility in a dry state to cause cracking, when it exceeds 50% bymass, the film softens and adhesion or melting occurs at hightemperature.

Furthermore, the film of the capsule for treating ulcerative colitis ofthe present invention, in order to achieve large intestine-specificdisintegration even when the hydrochloric acid concentration of thegastric juice is low due to anoxia or hypoacidity and the like, it isdesirable that the film contains an organic acid, an inorganic acid, apH adjuster, a compound containing divalent ions, or a combinationthereof. The material such as the organic acid can be applied to thesurface of the capsule, or the capsule immediately after formation canbe put into a dipping solution containing the compound such as theorganic acid to react.

In the capsule for treating ulcerative colitis of the present invention,in order to maintain or increase the therapeutic effect of indigo, anadherable substance to an epithelial of large intestine or a substanceincreasing residence time in the large intestine alone or in a mixturethereof can be also contained in any layer or layers of the capsule orapplied to the surface of the capsule.

Further, in the capsule for treating ulcerative colitis of the presentinvention, in order to maintain or increase the therapeutic effect ofindigo, the capsule can include a content which contains indigo powdercoated with the adherable substance to the epithelial of largeintestine. The capsule for treating ulcerative colitis of the presentinvention exerts a therapeutic effect by releasing the active ingredientindigo in the large intestine after reaching the large intestine andcoming into contact with inflammatory cells. Therefore, in order tomaintain or increase the therapeutic effect of indigo, it is alsodesired to extend the residence time in the large intestine by improvingthe intestinal epithelial adhesion of indigo.

The adherable substance to the epithelial of large intestine may be anysubstance that has a property of adhering to large intestine epitheliumand is pharmaceutically acceptable, and examples thereof includefat-soluble tocopherol (vitamin E), mucus glycoprotein mucin,polysaccharides produced by microorganisms such as bifidobacteria,polyphosphoric acid, basic polymers such as polyvinylpyrrolidone (PVP),polymers such as xanthan gum, guar gum, tamarind seed gum, gum arabic,alginic acid, pregelatinized starch, carboxyvinyl polymer (Carbopol 974PNF commercially available from CBC Co., Ltd., Hiviswako 103 commerciallyavailable from Wako Pure Chemical Industries, Ltd.), poly-N-vinylacetamide (PNVA), polyethylene glycol, polyvinyl alcohol, acrylicacid/acrylic acid octyl copolymer, silkfibroin acrylate copolymer resin,methacrylic acid/acrylic acid n-butyl copolymer, polyacrylicacid/acrylic acid octyl ester copolymer, acrylicacid-2-ethylhexyl/vinylpyrrolidone copolymer, methyl acrylate/acrylicacid-2-ethylhexyl copolymer resin, carmellose, hydroxyethyl cellulose,hydroxypropyl cellulose, methyl cellulose, carboxymethyl ethylcellulose, sodium carboxymethyl starch, crystalline cellulose,cyclodextrin, polyisoprene, polyacrylic acid and sodium polyacrylate,rubbers, and the like. In addition, the substance increasing residencetime in the intestine may be, similarly, any substance that has a longresidence time in the intestine, especially in the large intestine, andis pharmaceutically acceptable, and examples thereof include dietaryfibers such as indigestible dextrin. The most preferable adherablesubstance to the epithelial of large intestine is fat-soluble tocopherol(vitamin E), which is preferably contained in the content or protectivelayer. Amount of the substance falls within the range of 0.5 to 40% bymass of the whole capsule, and the coating amount falls within the rangeof 1 to 100% by mass of the whole capsule, and it is preferable that thecoating amount is amount that does not impair formulation properties ofthe capsule, and that does not inhibit capsule disintegration in thelarge intestine. In addition, the method for coating the indigo powderwith the adherable substance to the epithelial of large intestine is notparticularly limited, and examples thereof include a fine particlecoating method using a fluidized bed or the like. The amount of theadherable substance to the epithelial of large intestine, which isapplied to the indigo powder, preferably falls within the range of 0.1to 100% by mass of the whole indigo powder.

It is desirable that the dried film of the capsule of the presentinvention has a thickness of 10 to 600 μm, preferably 30 to 400 μm, andmore preferably 40 to 250 μm. When the thickness of the film is lessthan 10 μm, film strength is low, and when the thickness is more than600 μm, the amount of the content is small and disintegration is alsopoor.

In the production of the capsule for treating ulcerative colitis of thepresent invention, when a triple nozzle dropping method is used, it ispreferable to discharge the content from an innermost nozzle, dischargethe film from an outermost nozzle, and discharge an oily substance asthe protective layer from an intermediate nozzle. In this case, theobtained capsule has a triple-layered structure, and an innermostportion of the capsule contains the content, thus infiltration ofdigestive juice or the like from the outside is very small, which isconsidered to be the most excellent embodiment.

The capsule for treating ulcerative colitis obtained as described aboveis subjected to ventilation drying at 5° C. to 30° C. for 2 to 12 hours.Further, vacuum drying or vacuum freeze drying may be further performedafter ventilation drying. In vacuum drying, the degree of vacuum ismaintained at 0.5 to 0.002 MPa or less, and further in vacuum freezedrying, it is frozen at −20° C. or less and dried. The time required forvacuum drying or vacuum freeze drying is not particularly limited, butis generally 5 to 60 hours, and preferably 24 to 48 hours. When it isless than 5 hours, the drying is insufficient, and water present in thecapsule adversely affects the content.

The size of the capsule for treating ulcerative colitis of the presentinvention is not particularly limited, but it is desirable that thecapsule has a diameter of 0.3 to 10 mm, and preferably 1 to 8 mm. Whenthe diameter of the capsule is less than 0.3 mm, the thickness of theprotective layer of the three-layer structure is reduced and the effectof preventing infiltration of water is reduced, and when the diameter ismore than 8 mm, it is difficult to swallow.

The capsule for treating ulcerative colitis of the present invention isused for treating ulcerative colitis in humans and mammals. The capsuleis preferably administered orally. A dose of the capsule of the presentinvention depends on the subject (human and mammal), age, individualdifference, and medical condition, and for example, the daily dose foran adult (about 60 kg) is usually 0.05 to 120 mg/day, preferably 0.05 to80 mg/day, more preferably 0.05 to 20 mg/day, and most preferably 0.50to 15 mg/day, as the amount of indigo which is a drug for treatingulcerative colitis. Of course, the dose may be increased and decreasedaccording to the medical condition. Also, the administration may be oncea day or may be divided into multiple times.

The capsule for treating ulcerative colitis of the present invention hasa film having large intestine-specific disintegration, but thedisintegration mechanism is not a simple mechanism in which theoutermost layer of the multi-layered capsule disintegrates in eachenvironment, while proceeding to the stomach, small intestine and largeintestine in order, after oral administration. In the capsule of thepresent invention, a natural water-soluble polymer is used as a filmbase material, in which chitosan powder is dispersed in a compositematrix of a gel of a first natural water-soluble polymer such asgelatin, carrageenan and starch that imparts particularly excellentmechanical strength and film-forming ability and adhesiveness to acapsule, and an acid-resistant gel of a second natural water-solublepolymer such as pectin that imparts acid resistance, particularlygastric acid resistance.

First, the pH is very low in the stomach due to gastric acid, and thefirst natural water-soluble polymer that does not have gastric acidresistance is partially eroded by gastric acid, but the content isprotected by a film (preferably in combination with a protective layer)of the second natural water-soluble polymer that has gastric acidresistance. At the same time, the chitosan powder that was dispersed inthe natural water-soluble polymer changes to sol (solution state) in theacid resistant film due to the acidic aqueous solution, but the contentdoes not easily flow outside the capsule because there is chitosan soldispersed in the acid resistant film. Then, the capsule for treatingulcerative colitis proceeds to the small intestine in such a state, butthe pH rises in the small intestine and the acid resistant filmdisintegrates, and at the same time, the chitosan sol dispersed in thenatural water-soluble polymer is gelled to form a chitosan film, and thecontent is protected by the chitosan film and the protective layer.Finally, in the large intestine, the chitosan film is specificallydecomposed by organic acid and enzyme such as lysozyme produced by alarge number of anaerobic microorganisms, and the protective layer ofthe capsule also disintegrates to release the content (that is, indigowhich is an active ingredient for treating ulcerative colitis).

In the capsule for treating ulcerative colitis disintegrating in thelarge intestine of the present invention, indigo which is an activeingredient for treating ulcerative colitis that has been protected up tothe large intestine is released in the large intestine to exert itsmedicinal effect. In addition, in order to maintain or increase thetherapeutic effect of indigo, an adherable substance to an epithelial oflarge intestine or a substance increasing residence time in the largeintestine alone or in a mixture thereof is added to any layer or layersof the capsule or applied to the surface of the capsule, or the capsuleincludes a content containing indigo powder coated with the adherablesubstance to the epithelial of large intestine, thereby greatly reducingulcerative colitis.

EXAMPLES

The present invention will be described in more detail by way ofexamples. The present invention should not be construed as limited tothese examples.

Preparation Example 1 Formation of Indigo-containing Capsule A

(a) Content liquid: a dispersion of 8.33 g of indigo (manufactured byTokyo Chemical Industry Co., Ltd., purity 97%) in a melt of 91.67 g ofan oily substance (glycerin fatty acid ester) with a melting point of32° C. was prepared as a content liquid.

(b) Protective layer liquid: 90.00 g of glycerin fatty acid ester(melting point 42° C.), 7.00 g of lecithin and 3.00 g of fine silicondioxide were mixed to obtain a protective layer liquid.

(c) Film liquid: 67.00 g of acid-treated gelatin derived from pig skin(jelly strength: 240 Bloom), 24.00 g of food additive concentratedglycerin, 3.00 g of low methoxyl (LM) pectin (DE value of esterificationdegree: 27) and 6.00 g of squid chitosan (acetylation degree: 80 ormore; particle size: 90% or more passing through a sieve having anopening size of 250 μm (60 mesh), according to sieve test standard JISZ8801) were mixed to obtain a film liquid.

A seamless capsule having a three-layered structure was formed bysimultaneously dropping the content liquid from an inner nozzle of aconcentric triple nozzle, the protective layer liquid from anintermediate nozzle outside thereof, and the film liquid from anoutermost nozzle into a cooled and flowing oil. The obtained capsule wasdried by aeration at 20° C. for 6 hours to prepare an indigo-containingcapsule A having a three-layered structure. A diameter of the capsule Awas 1.9 mm and a weight of the capsule A was 3.89 mg. An indigo contentper the capsule A was 0.1 mg.

Creation of Colitis Mice

As mice used in an animal test, C57BL/6J was started to use afterpreliminary breeding for 3 days after purchase. First, a 2.0% solutionof DSS (dextran sulfate sodium salt, molecular weight 36,000 to 44,000)was given to mice to cause colitis to prepare colitis model mice.

Control Mice

The colitis model mice were administered with only sterilized water toobtain control mice. It should be noted that, in order to maintain thecolitis state of the mice for 7 days, the 2.0% DDS (dextran sulfatesodium salt) solution was orally administered at the same time as theadministration of the sterile water.

Example 1

Five capsules (equivalent to indigo amount of 0.5 mg) and 15 capsules(equivalent to indigo amount of 1.5 mg) both of which were theindigo-containing capsules A were each orally administered to 5specimens of colitis mice for 7 days. It should be noted that, in orderto maintain the colitis state of the mice for 7 days, the 2.0% DDS(dextran sulfate sodium salt) solution was orally administered at thesame time when the oral administration of the capsules A.

Evaluation Results

Colitis-suppressing action of indigo was evaluated by a decrease in theendpoints such as body weight (BW), disease activity index (DAI) score(DAI score: a total score (0 to 12) of the number of defecation, bloodystool, mucosal findings, and general endpoints scored 0 to 3 on a4-point scale), and colon length. Since body weight loss, increase indisease activity index core, and shortening of the colon length wereobserved with progress of pathological condition of colitis, theintestines of the mice after administration were examined, and thepresence or absence of colitis was determined by the above endpoints.

The results of the evaluation measurements are represented in FIG. 2 toFIG. 4. It should be noted that FIG. 1 is a pictorial form of the typesof mice used in the evaluation for easy understanding. FIG. 5 representsindigo hepatotoxicity confirmed with serum ALT index, which was measuredin control and capsule-administered mice.

FIG. 1 is a pictorial form of the types of mice used in the evaluationfor easy understanding, in which the left picture is a mouseadministered with 200 μL of sterilized water as a control, the secondfrom the left is a mouse administered with 5 indigo-containing capsulesA per day (equivalent to indigo amount of 0.5 mg/day), and the rightmostis a mouse administered with 15 indigo-containing capsules A per day(equivalent to indigo amount of 1.5 mg/day).

FIG. 2 is a graph representing changes in body weight (BW) of mice for 7days. The rate of change in the average body weight of the mice of eachembodiment is described, with the average value of the body weight atthe start of the experiment being 100%. As is clear from FIG. 2, theindigo-containing capsule administration groups (5 tablets (equivalentto indigo amount of 0.5 mg/day) and 15 tablets (equivalent to indigoamount of 1.5 mg/day)) showed less body weight loss, and thepathological condition of colitis was clearly mild.

FIG. 3 is a graph representing results of disease activity index score(DAI score). It should be noted that the DAI score refers to anevaluation index described in the literature “Sutherland L R, Martin F,Greer S, et al: 5-Aminosalicylic acid enema in the treatment of distalcolitis, proctosigmoiditis, and proctitis. Gastroenterology 92:1894-1898, 1987”.

As is clear from FIG. 3, the pathological condition of colitis in thegroups administrated 5 indigo-containing capsules A (equivalent toindigo amount of 0.5 mg/day) and 15 indigo-containing capsules A(equivalent to indigo amount of 1.5 mg/day) were significantlyalleviated in both low and high doses than that in the control group.Based on the above, it could be confirmed that the indigo-containingcapsule A administration groups suppressed colitis with a lower dose ofindigo.

FIG. 4 is a graph representing results of measuring colon length. Sincethe colon length is shortened by causing colitis, the colon length ofeach mouse group was measured as another index for the evaluation ofcolitis, and the average value thereof was represented by a histogram.

As shown in FIG. 4, the indigo-containing capsule administration groups(equivalent to indigo amounts of 0.5 mg and 1.5 mg/day) showed asignificantly longer colon length than the control group. Based on this,it could be confirmed that the indigo-containing capsule administrationgroups suppressed colitis even at a lower concentration of indigoamount.

Regarding the mice that were orally administered with indigo powder asit was (equivalent to indigo amount of 0.5 mg/day) for 7 days, theresults are not represented in FIGS. 2 to 4. However, as a result of theexperiment, decreasing the body weight was also observed as comparedwith the control group, and the colon length was also the same as thatof the control group, thus no effect of indigo was observed.

FIG. 5 is a graph representing indigo hepatotoxicity confirmed withserum ALT index. The serum ALT index was measured by ultravioletabsorptiometry described in JSCC (Japan Society of Clinical Chemistry)standardization method.

There was no difference between indigo-containing capsule A and indigopowder when evaluated using the ALT level as an endpoint. However, at0.5 mg/day, where the indigo-containing capsule A showed a strong effectand the powder showed no effect, the indigo-containing capsule A had anALT level equivalent to that of the control.

Based on these results, it was revealed that oral administration of 0.5mg/day of indigo-containing capsule A can suppress the pathogenesis andprogression of colitis in a mouse model of colitis without causing liverdysfunction. In other words, it was found that indigo-containing capsuleA could provide a therapeutic window without indigo being contacted andabsorbed in the small intestine.

Since the capsule of the present invention showed an effect at a lowdose (equivalent to 25 mg/kg/day) showing no effect in powderadministration even when compared with the low dose (60 mg/kg/day) ofindigo powder described as effective in Non Patent Literature 4 incolitis model mice, it was shown to be a therapeutic agent forulcerative colitis at a lower dose than administration by powder, andhas little fear of side effects. Therefore, it can be provided as a drugthat has little burden on the patient and little fear of side effects.

Example 2

In order to cope with high pH due to hypoxia, the indigo-containingcapsule A of Preparation Example 1 was acid-treated in advance andre-dried to create a capsule, and a disintegration test was performed.

A capsule containing indigo that had been immersed in an acidic solutionfor 3 minutes or more was prepared, and immersed at pH 4.0, which is thepH assumed in the stomach of a mouse, at 37° C. for 60 minutes toperform a disintegration test. After 60 minutes, the capsule was takenout into a petri dish and photographed to confirm the state of thecapsule. No disintegration of the capsule and no outflow of indigo inthe capsule were observed.

Example 3

The following indigo-containing capsule B was formed in the same manneras the formation of the indigo-containing capsule A of PreparationExample 1.

(a) Content liquid: a dispersion of 8.33 g of indigo (manufactured byTokyo Chemical Industry Co., Ltd., purity 97%) in a melt of 85.67 g ofan oily substance (glycerin fatty acid ester) with a melting point of32° C., 3.00 of lecithin and 3.00 of tocopherol was taken as a contentliquid.

(b) Protective layer liquid: same as the one in the indigo-containingcapsule A.

(c) Film liquid: same as the one in the indigo-containing capsule A.

In order to confirm improvement in adhesion to the large intestine, anin vitro test was performed using the following two types of platesassuming large intestine cells (both manufactured by CorningInternational K.K.).

(1) BioCoat™ Fibronectin 6 well plate (coating component: fibronectin)

(2) BioCoat™ Poly-D-Lysine/Laminin 6 well plate (coating component:poly-D-lysine/laminin)

The indigo-containing capsule A and the indigo-containing capsule B wereeach immersed in purified water at 10° C. for 5 minutes, so that thefilm was swelled and then peeled off and removed, and they were added toand dissolved in a digestive enzyme solution (Japanese PharmacopoeiaDisintegration Test Solution II added with pancreatin, yatalase and asurfactant), and the dissolved liquids were designated as capsule A atthe time of large intestine disintegration and capsule B at the time oflarge intestine disintegration (prescription for studying improvement inadhesion to the large intestine), respectively.

The capsule form A at the time of large intestine disintegration and thecapsule B at the time of large intestine disintegration (prescriptionfor studying improvement in adhesion to the large intestine) were eachplaced on the above-mentioned two types of plates assuming largeintestine cells and dissolved in an incubator at 37° C. After stirringat 500 rpm for 1 hour, the Japanese Pharmacopoeia Disintegration TestSolution II was added thereto, and unattached indigo was removed. Next,dimethyl sulfoxide (DMSO) was added thereto, the mixture was furtherstirred for 10 minutes, and DMSO obtained by dissolving and extractingindigo adhering to the plates assuming large intestine cells was eachcollected as sample solutions.

The adhesion rate of these sample solutions was determined byquantification using liquid chromatography (HPLC). Based on theseresults, more significant improvement in adhesion of indigo to the largeintestine epithelial cells was confirmed in the capsule B which is adrug obtained by adding tocopherol to the content liquid of the capsulethan the capsule A.

INDUSTRIAL APPLICABILITY

The present invention is directed to a capsule for treating ulcerativecolitis. The capsule is a capsule that does not easily disintegrate inthe stomach and small intestine when delivered orally, and is deliveredto the large intestine and disintegrates to exert its effect. Thepresent invention suppresses onset of pulmonary arterial hypertension,which is a serious side effect, and greatly contributes to treatment ofulcerative colitis that is intractable and extremely bad for quality oflife (QOL), by “reduction of the amount of indigo to be administered”and “specific delivery of indigo to the large intestine”. Further, inorder to maintain or increase the therapeutic effect of indigo, anadherable substance to an epithelial of large intestine or a substanceincreasing residence time in the large intestine alone or in a mixturethereof is blended in any layer or layers of the capsule or applied tothe surface of the capsule, or the capsule includes a content containingindigo powder coated with the adherable substance to the large intestineepithelial, thereby greatly reducing ulcerative colitis.

1. A capsule for treating ulcerative colitis which disintegrates locally in the large intestine, comprising a drug-containing content, a protective layer coating the content and a film formed outside the protective layer, which are arranged concentrically, wherein the content is a content in which indigo is dispersed or dissolved, the indigo being a drug for treating ulcerative colitis, the protective layer contains an oily substance, the film is a film which chitosan powder is dispersed in a film base material of a natural water-soluble polymer, and the natural water-soluble polymer is a mixture of a first natural water-soluble polymer and a second natural water-soluble polymer, the first natural water-soluble polymer is composed of one or a mixture of at least two selected from the group consisting of gelatin, carrageenan, starch, agar, pullulan, modified starch, alginic acid and mannan, and the second natural water-soluble polymer is composed of one or a mixture of at least two selected from the group consisting of pectin, gellan gum and curdlan.
 2. The capsule for treating ulcerative colitis according to claim 1, wherein the film further contains a plasticizer.
 3. The capsule for treating ulcerative colitis according to claim 1, wherein the chitosan powder is of animal origin or plant origin, and amount of the chitosan powder falls within the range of 1 to 27% by mass, and amount of the second natural water-soluble polymer falls within the range of 1 to 24% by mass, based on the total weight of the dried film.
 4. The capsule for treating ulcerative colitis according to claim 1, wherein the film base material of the natural water-soluble polymer is a mixture of gelatin and pectin.
 5. The capsule for treating ulcerative colitis according to claim 1, which has been treated with an acidic solution in advance.
 6. The capsule for treating ulcerative colitis according to claim 1, wherein one selected from the group consisting of the content, the protective layer and the film or a combination thereof further contains an adherable substance to an epithelial of large intestine, a substance increasing residence time in the large intestine or a combination thereof.
 7. The capsule for treating ulcerative colitis according to claim 1, wherein an adherable substance to an epithelial of large intestine, a substance increasing residence time in the large intestine or a combination thereof is allowed to be present on the outer surface of the film.
 8. The capsule for treating ulcerative colitis according to claim 1, comprising the content which contains indigo powder and an adherable substance to an epithelial of large intestine, wherein the indigo powder is blended or coated with the adherable substance to the epithelial of the large intestine.
 9. The capsule for treating ulcerative colitis according to claim 1, which is for oral administration.
 10. The capsule for treating ulcerative colitis according to claim 1, which is administrated in amount of indigo per adult (60 kg) of 0.05 to 120 mg/day.
 11. The capsule for treating ulcerative colitis according to claim 1, which is administrated in amount of indigo per adult (60 kg) of 0.05 to 20 mg/day. 